India’s space ambitions have taken another significant step forward with the successful vacuum ignition test of the CE20 cryogenic engine, conducted on February 7, 2025, at the Indian Space Research Organisation’s (ISRO) Propulsion Complex in Mahendragiri, Tamil Nadu. This test, which simulated the engine’s operation in the vacuum of space, is an important milestone in validating the engine’s performance under real mission conditions. The CE20 engine, designed for the upper stage of the LVM-3 rocket, is expected to play a crucial role in future ISRO missions, including the much-anticipated Gaganyaan human spaceflight programme.
The main objective of the test was to assess the engine’s restart capabilities in a vacuum environment, which is essential for long-duration missions. The CE20 cryogenic engine is equipped with a multi-element igniter that enables it to restart its thrust chamber. The test specifically focused on ensuring that the engine can maintain the necessary tank pressure for restart, a critical requirement for the flexible and reliable performance of rockets in space. With a demonstrated thrust range of 19 to 22 tonnes, the engine has previously been tested for a single-start scenario, but this recent trial explores the engine’s capability to perform multiple restarts during flight.
As part of ongoing research, ISRO is considering the introduction of an innovative approach to turbopump initiation, known as the bootstrap mode. This method could potentially replace the conventional stored gas systems typically used to start the engine’s turbopump. If successful, this alternative could enhance the efficiency and reliability of the engine’s restarts. Previous ground-based trials have confirmed the engine’s ability to function under various conditions, and the success of the vacuum test is another key step toward qualifying the CE20 for use in more complex missions.
The CE20 engine plays a pivotal role in the upcoming Gaganyaan mission, India’s first manned spaceflight initiative. With these recent successful tests, ISRO is one step closer to ensuring that the engine will perform reliably in the demanding environment of space. The successful vacuum test has further bolstered confidence in the engine’s readiness for future space exploration tasks, ensuring that ISRO’s planned missions, including human space travel, can proceed with greater confidence in the technology’s capabilities.